Direct-acting compressed-air brake.



No. 732,856. PATENTED JULY 7, 1903;

w. K. M. HILDEBRAND.

DIRECT ACTING COMPRESSED AIR BRAKE.

. APPLIOATION FILED JUNE 16. 1902.

110 MODEL.

Patented July 7, 1903.

WILHELM KARL MAX I-IILDEBRAND, OF GROSSJJUHTERFELDE, NEAR BERLIN, GERMANY.

DIRECT-ACTING COMPRESSED-AIR BRAKE.

SPECIFICATION forming part of Letters Patent No. 732,856, dated July 7, 1903.

Application filed June 16, 1902. $erial No. 111,893- (No model.)

10 all whom it may concern. Be it known that I, WILHELM KARL MA HILDEBRAND, engineer, a subject of the King of Prussia, German-Emperor, residing at Berlinerstrasse 4:6, Gross-Lichterfelde, near Berlin, Germany, have invented certain new and useful Improvements in-Direct-Acting Compressed-Air Brakes, of whichthe following is a specification.

Myinvention relates to a direct-acting compressed-air brake, by means of which even. long trains may be rapidly and effectively braked.

Hitherto with direct-acting compressed-air paratus the air stored up in the main air-reservoir is conducted from the drivers footplate in a slow stream into the brake-pipe running throughout the length of the train and from there direct to the various brake-cylinders. For rapid braking, on the other hand, by increasing the pressure in the main pipe the direct path from the brake-pipe to the brake-cylinder is closed and valves connected with the brake-pipe actuated in such manner that the auxiliary air-reservoir located on each carriage is connected with the corre-' small, while the connection with the brakepipe is larger. A large quantity of air, therefore, rushes first into the brake-pipe, so that the pressure in the latter israpidly transmitted, and the air, even with the longest trains, almost simultaneously fills all the brake-cylinders.

One construction of my new apparatus is illustrated by the annexed drawings, in

which Figure l is a vertical section of the device,

the piston being at the bottom of its cylinder. Fig. 2 is a like view, the piston being at the top of the cylinder. Fig. 3 is a crosssection taken on the line A B of Fig. 1. i

For ordinary braking the driver by slightly opening his brake-valve allows the air to slowly escape from the main air-reservoir into the brake-pipe a. From this it flows further through a branch pipe I), through the valve 0, which is maintained in open position by gravity or spring-pressure, and through the pipe 01 direct to the brake-cylinder, to which this pipe is connected. The current of air in the valve 0 during this time is so small that it is unable to lift the valve, which accordingly remains open. The difference of pressure between the pipes 12 and d is consequently not great enough to lift the double piston e e of the distributing-valve h, connected to the brake-pipe. The top chamber at of the valve 72 is in direct connection with the pipe d and the bottom chamber 0 with the pipeb. described, in no way differs from any ordinary slow braking with direct-acting compressed-air brake. If, however, it is desired to brake rapidly, the driver must fully open his valve. The air from the main air-reservoir thus enters the pipe on suddenly and in large volume, so producing increased pressure. In passing further through the branch pipe I) it will now close the valve 0, which does not offer sufiicient passage for it. The higher pressure in the pipe I) and bottom chamber 0 of the valve h as compared with the pressure in the pipe at and top chamber 'nwill now displace the double piston c c, with the rings g g rigidly mounted on its spindle, so as to occupy the position shown in Fig. 2. In this position the rings 9 g set free the recessed passages t' and 70, running around the cylinder h. The space between the two piston-heads e e is directly connected to the auxiliary air-receptacle by the pipe m. The air stored up in the auxiliary air-reservoir there- This manner of braking, just portion of the pipe b above the valve 0 and further through the pipe d directvinto the brake-cylinder, filling this instantaneously with air. At the same time the air of the auxiliary air-reservoir also passes through the perforations of the lower ring g, through the passage 1 and pipe Z into the brake-pipe a, so that it can contribute tostrengthen the current already present in it, and. thereby assist the transmission of the braking action through the entire train. Since now the passage 7; is considerably wider than the passage is, a large quantity of air first flows into the brake-pipe, and thereby increases the current in the latter, so that in a minimum space of time the whole of the valves for rapid braking connected to the brakepipe are actuated. Since the small section of the passage 70 retards the passage of air into the brake-cylinder, the brake-cylinder of the first carriage is not yet filled when the air begins to flow into the brake-cylinder of the last carriage, and the braking throughout the entire train takes place. The releasing of the brakes is produced by turning the drivers valve in such a position that the brake-pipe is in communication with the outer air. The air inclosed in the brakecylinders then escapes through pipes d and b, past the opened valve 0 and the pipe a. Before the air has escaped from the brakecylinder the equality of pressure in the chambers n and 0 has caused the double piston e to return to its original position, as shown in Fig. 1, so that the auxiliary air-reservoir has been cut off-from pipe'a, and therefore air cannot escape from the former.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A valve mechanism for direct-acting compressed-air brakes, comprising a valve 0 in the direct passage from brake-pipe to brakecylinder, only closing at high pressure in the brake-pipe, and a distributing-valve h connecting the auxiliary air-reservoir with the brake-pipe and with the brake-cylinder, and only opening when said valve 0 closes, all substantially as and for the purposes described.

2. A valve mechanism for direct acting compressed-air brakes, comprising a valve 0 in-the branch between brake-pipe and brakecylinder, only closing at high pressure in the brake-pipe, and a valve h consisting of a cylinder connected to the auxiliary air-reservoir, and having passages communicating above and below said valve 0, a piston controlling said passages, and passages leading to the brake-pipe and the brake-cylinder also controlled by said piston, said valve h'only opening when the valve 0 closes, all substantially as and for the purposes described.

3. A valve mechanism for direct acting compressed-air brakes, comprising a valve 0 in the branch between brake-pipe and brakecylinder, only closing at high pressure'in the brake-pipe, and a valve h consisting of a cylinder connected to the auxiliary air-reservoir, and having passages communicating above and below said valve 0, a piston controlling said passages, and passages leading to the brake-pipe and brake-cylinder also controlled by said piston, the former passage being considerably larger than the latter, so that the air from the auxiliary air-reservoir may first augment the current in the brake-pipe and then slowly fill the brake-cylinder, said valve it only opening when the valve ccloses, all substantially as and for the purposes described. Signed at Berlin this 29th day of May, 1902.

WILl-IELM KARL lllAX IIILDEBRAND. Witnesses:

WOLDEMAR HAUPT, HENRY HASPER. 

